http://librarian.i2p/get/11341576559898998396/2309196205305292271
= get(key) end end puts (h.isNot? 'k1', 'v1') puts (h.isNot? 'k2', 'v3')However, any added methods are only visible to the JRuby runtime. If you were to pass an instance of this modified HashMap class to Java code, the new methods would not be available.JRuby also includes a utility method called extend_proxy that allows you to add new methods to all implementations of a particular interface.